RE: xylene substitutes revisited

Acute (short-term) inhalation
exposure to mixed xylenes in humans results in irritation of the nose and
throat, gastrointestinal effects such as nausea, vomiting, and gastric
irritation, mild transient eye irritation, and neurological effects.

Chronic (long-term) inhalation exposure of humans to mixed xylenes results
primarily in central nervous system (CNS) effects, such as headache,
dizziness, fatigue, tremors and incoordination. Other effects noted
include labored breathing and impaired pulmonary function, increased heart
palpitation, severe chest pain and an abnormal EKG, and possible effects on
the blood and kidney.

The Reference Concentration (RfC) for mixed xylenes, m-,
o-, and p-xylenes is under review by the U.S. Environmental
Protection Agency (EPA).

The Reference Dose (RfD) for mixed xylenes is 2 mg/kg/d.a The
provisional RfD for m- and o-xylenes is also 2 mg/kg/d. EPA
estimates that consumption of this dose or less, over a lifetime, would not
likely result in the occurrence of chronic noncancer effects.b

Insufficient data are available on the developmental or reproductive
effects of mixed xylenes in humans. Animal studies have reported
developmental effects, such as an increased incidence of skeletal
variations in fetuses, and fetal resorptions via inhalation.

No information is available on the carcinogenic effects of mixed xylenes
in humans, and animal studies have reported negative results from exposure via
gavage (experimentally placing the chemical in the stomach). EPA has
classified mixed xylenes as a Group D, not classifiable as to human
carcinogenicity.

THIS is why some of us don't want
xylenes in our labs. If you've ever felt dizzy while coverslipping(and
don't have the $$ for an automatic coverslipper) or have gone home with headache
after headache... Personally, I have no desire to even come CLOSE to
chronic exposure limits, especially when there are multiple
options!!!

Well, I worked for many years in a lab
that used Histo-clear (citrus-based) exclusively and we had no problems with
anything, including immunos. So I can't help you in "heading them off at the
pass."

On the other hand, I can't see using
xylene as a bad thing as long as proper safety precautions are taken. One good
one is to use an automated coverslipper so that xylene exposure to skin is
greatly limited. Since the critical exposure levels to xylene vapors are quite
high, that is not usually a problem. Is there some reason xylene is being
phased out?

Of course finding a xylene substitute that
is acceptable to everyone in the lab is very tough. It seems there is a
problem with all of them in some way, either some can't stand the odor of one
or another, or there are sensitivity issues that rival xylene. Good
luck!

Good morning everyone. Our safety committee is all set to switch us to
a xylene substitute. In order to head them off at the pass, I'd like any
info you kind people can provide concerning the impact xylene sub's would
have on IPX as well as on routine tissue preparation; processing, staining,
special stains, well you know, the whole nine yards!